According to prior art a television receiver displaying a normal picture on the screen of the picture tube includes means for additionally displaying characters on a part of the screen (i.e., a minor portion of the screen) within the normal picture (i.e., the major portion of the screen). Said characters may include an explanation of the normal picture just displayed. They may include any news or special hints for the controlling or tuning or adjusting of the receiver.
The characters in form of symbols, letters or numbers may be merely inserted into the picture so that only the characters themselves occupy a part of the picture area. In other cases a so-called box is provided within the picture area and the characters appear within said box. The box forming a background for the characters may be displayed in black or any other color.
If the characters are located within a box having a background with uniform color a good visibility of the characters is achieved as the characters within the box are not surrounded by the normal picture. On the other hand a part of the normal picture is lost and cannot be regarded. This is a disadvantage especially in cases where the box occupies a relative large area of the picture.
Another solution consists of displaying the normal picture also within the box. In this case the normal picture can be seen within the area occupied by the box except the small areas of the characters. However, in this case it becomes difficult to read the characters as they are surrounded by the normal picture. Said two demands for display of nearly the full picture also in the box on the one hand and a good visibility of the characters on the other hand therefore seem to be contrary and not possible simultaneously.